Background: The capsid (Cap) protein of PCV2 is the major immunogenic protein that is crucial to induce PCV2-specific neutralizing antibodies and protective immunity; thus, it is a suitable target antigen for the research and development of genetically engineered vaccines against PCV2 infection.IFN-gamma has exhibited potential efficacy as an immune adjuvant that enhances the immunogenicity of certain vaccines in experimental animal models, consideration of IFN-gamma as a component of vaccine formulations is therefore warranted.